Not Applicable
Not Applicable
Not Applicable
The invention herein relates to a steering column switch comprising a support for individual switches, which are mounted to a jacket tube of a steering column of a motor vehicle, and a housing.
Usually, steering column switches are arranged radially with respect to the steering column on said steering column""s jacket tube, whereby the actuation of the steering wheel and hence the steering column in the jacket tube do not result in a movement of the steering column switch relative to the steering wheel. As a rule, steering column switches comprise a blinker switch, a driving-lights switch that is integrated in the switch lever of the blinker switch, and a wiper switch for the incremental actuation of the windshield wipers and for the switching functions of the windshield washer system. Such steering column switches have been known, for example, from (German) documents DE-AS 28 10 790 and DE 35 32 532 C2. Each steering column switch comprises a plurality of actively interacting components, thereby realizing a large number of switching functions. Depending on the type of vehicle, individual components are pre-assembled and then mounted to a support on the steering wheel jacket tube.
In a typical application the support acts as support for many different individual switches of the steering column switch and, consequently, must exhibit relatively high rigidity. Therefore, this support is made of plastic materials which have been reinforced with glass fibers or similar materials. As a result of aligning the glass fibers in the hardened plastic melt, these fibers are visible on the surface of the support, which, for design reasons, is considered undesirable. In order to protect the individual switches mounted to the support against environmental effects and hence against damage, the support is associated with a housing, which, in order to make it sturdy, is fabricated of a reinforced plastic material. In order to adapt the steering column switch to the vehicle interior or to achieve a pleasant appearance, an exterior housingxe2x80x94a so-called design sleevexe2x80x94is mounted to the support and the housing. For assembly and manufacturing reasons the exterior housing is at a distance from the support and the housing, which is why the steering column switch requires correspondingly more space.
The problem to be solved by the invention herein is to provide a steering column switch of the above-described type, which accommodates individual switches while making maximum use of space, is inexpensive to manufacture and designed in a visually pleasing manner.
In accordance with the invention herein this problem has been solved in that at least the visible wall portions of the housing and at least the visible wall portions of the support each consist of a core and a sleeve that are connected with each other in one piece.
The assembly of the present invention thus eliminates the need for an additional design sleeve or an additional exterior housing for the support and for the housing. Considering a given availability of space for the steering column switch, said switch has a relatively large interior space for the accommodation of associate switches because the one-piece connection of the respective cores and sleeves of the visible wall portions of the housing and the support eliminates any empty space between them.
The core must be considerably more sturdy than the sleeve. Therefore, the core preferably consists of a plastic material exhibiting relatively high rigidity and the sleeve of a plastic material exhibiting relatively low rigidity. Consequently, the core, for example, is manufactured of a plastic material which has been reinforced with glass fibers, has a relatively rough surface and is of lesser quality, whereas the sleeve consists of an unfilled plastic material with a surface quality that is higher than that of the core. Plastic materials which are used for manufacturing decorative visible surfaces usually exhibit relatively low rigidity. Furthermore, additional known fillers may be admixed to the work material for the core, if desired, for altering the electrical properties of the work material. In order to adapt the appearance of the sleeve to the surface properties of adjacent components of the steering column switch or to mount adjacent components to the sleeve, this sleeve preferably consists of a plastic material exhibiting properties which satisfy given requirements.
It is useful if the core and sleeve are produced by means of a two-component injection molding process. In this manner, the different materials can be processed to produce one inexpensive high-quality component by means of one manufacturing process.
Inasmuch as the sleeve must satisfy primary design requirements relating to the column and secondary requirements relating to mechanical and/or electrical properties, one development of the invention herein relates to a sleeve that has a lower wall thickness than the core. Therefore, to meet these requirements, the sleeve can be manufactured during a relatively short injection cycle and with a relatively low use of material.
In order to adapt the appearance of the steering column switch to other components installed in the motor vehicle""s interior, the sleeve is preferably provided with a structured surface.
In accordance with an advantageous embodiment of the inventive idea the sleeve and the core of the respective wall portions of the housing are provided with cutouts for the actuation elements of the individual switches. For this purpose the sleeve encloses at least part of the wall of the core cutout. As an alternative, the sleeve projects slightly beyond the wall of the core cutout. Such an arrangement provides assembly openings for the actuation elements, whereby the core is covered at the abutting edges of the latter. This ensures a uniform appearance of the steering column switch.